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Full text of "Preliminary screening of emulsifiable toxaphene concentrates"

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September 1952 E-847 

^TE^f board 

01 United States Department of Agriculture 

Agricultural Research Administration 
Bureau of Entomology and Plant Quarantine 



1/ 



PRELIMINARY SCREENING OF 
EMULSIFIABLE TOXAPHENE CONCENTRATES^ 

B. I. Sparr^ 
Division of Insects Affecting Man and Animals 



In the application of toxaphene emulsions by power spraying, the 
stability of the emulsion presents only a minor problem. However, 
where the stock is dipped in a vat the stability of the emulsion is of 
major importance. Experiments were therefore conducted to develop 
emulsifiable toxaphene concentrates that would yield stable emulsions. 
A method for screening candidate concentrates containing different 
emulsifiers is described, and the results of screening some formula- 
tions are reported. Another consideration was the use of agricultural 
products in insecticide formulations; hence the testing of turpentine and 
pine oil as solvents. 

Formulations Tested 

Three types of formulations were tested: 

(1) Three experimental concentrates containing 50 percent of toxa- 
phene, 10 percent of emulsifier, and 40 percent of one of the following 
solvents: kerosene, pine oil (sp. gr. 0.9358 at 15.6°/ 15.6° C), or 
turpentine (all percentages by weight). 

(2) Three commercial concentrates: 

(A) Toxaphene 65, aliphatic hydrocarbon solvent 25, alkylaryl 
poplyethylene glycol 7.5, and alkylaryl sulfonate 2.5 percent. 



1/ Report of a study made under the Research and Marketing Act of 
1946~. 

2/ The author is indebted to H. F. Beckman, R. C. Bushland, H. V. 
Claborn, and R. D. Radeleff for advice and occasional assistance in these 
studies. 



- 2 - 

(B) Toxaphene 60, aliphatic hydrocarbon solvent 22, aromatic 
hydrocarbon solvent 5, alkylaryl polyethylene glycol 5, poly- 
ethylene glycol ester 5, and polyoxyethylene sorbitol oleate- 
laurate 3 percent. 

(C) Toxaphene 50, alkylaryl polyethylene glycol 4, phthalic 
glycerol ajkyd resin 6, epichlorhydrin 0.2, and petroleum 
distillate 39.8. 

(3) A miscellaneous group of formulations suggested by various 
emulsifier manufacturers. 

The specific gravities at 25° C, of the solutions of toxaphene in the 
experimental concentrates were determined, and for this work were con- 
sidered as constant with respect to temperature. The volume containing 
5 grams of toxaphene for each solution was used for making the test 
emulsions. 

Preparation of Emulsions 

The following procedure was adopted for preparing the emulsions: 

One gram of emulsifier was weighed into a 50-ml. beaker. The 
volume of the kerosene, pine oil, or turpentine solution containing 
5 grams of toxaphene was pipetted into the beaker and the mixture 
stirred to dissolve the emulsifier. When necessary, gentle heat was 
applied. Distilled water was then added slowly until an oil-in-water 
emulsion was formed. This emulsion was poured into a 500-ml. grad- 
uated cylinder and diluted with distilled water to 500 ml. to produce a 
1 -percent toxaphene emulsion. It was then poured into a 1 -liter 
Erlenmeyer flask, stoppered, and shaken for 30 seconds. Into each 
of five calibrated vials, 9.7 cm. long and 2.4 cm. inside diameter, 
15 ml', of the freshly shaken emulsion was poured. The emulsion was 
further diluted to contain 0.5 percent of toxaphene by adding to each vial 
an equal volume of distilled water, tap water (containing 14 grains of 
calcium carbonate per gallon), 2-percent acetic acid, ammonium 
hydroxide, or sodium chloride. The vials were placed in racks and left 
open to the air. 

Observations and Screening Criteria 

The emulsions were examined after 1 hour, 1 day, and 1 week. 
Observations were made on the extent of bottom creaming as measured 
with a millimeter rule, the degree of top clearing, any phase separation, 
the ease of re-emulsification of the separated oil or ease of resuspension 
of the cream, and the discernibility of resuspended particles when the 
vials were illuminated by flashlight. 



-3- 



Since for use in dipping vats a stable emulsion with a slow rate of 
creaming was desirable, the following criteria were established for 
choosing the more promising formulations: 

(1) The emulsifier was soluble in the toxaphene solution. 

(2) No bottom creaming, or only a trace, appeared in any vial at 
the end of a week. 

(3) There was no oil separation in any of the aqueous media, except 
the 1 -percent sodium chloride system, at the end of a week. 

(4) The cream was readily redispersed on inversion of the vial. 

(5) Upon illumination of the vial after inversion, there were no 
individually discernible particles. 

(6) There was either no top clearing or only slight clearing, 

Since no pine-oil concentrates conformed to criterion (2), the pine- 
oil emulsions chosen for further consideration showed 1 mm. or less 
of bottom creaming, but met the other criteria. 

Results 



Experimental concentrates . --In the course of testing the experi- 
mental concentrates 103 emulsifiers were tried. The following were 
found to give satisfactory formulations with at least one type of toxa- 
phene emulsion, according to the criteria outlined above. 

Emulsifier Solvents 

Ahco RL 382 (Arnold, Hoffman & Co.) Kerosene 

Ahcowet Anhydrous RS (Arnold, 

Hoffman & Co.) --------------- Kerosene and turpentine 

Antarox D-100 (General Dyestuff Corp.) - - - Pine oil 

Chlorsol (E.F. Drew & Co.) --------- Pine oil and turpentine 

Duponol G (E.I. du Pont de Nemours & Co.) - Kerosene 

Emcol H-77 (Emulsol Corp.) Pine oil 

Emulside 75 (Van Dyk & Co.) -------- Kerosene 

Emulsifier 803-M (E. F. Drew & Co.) Turpentine 

Emulsifier R (Monsanto Chemical Co.) - - - Kerosene 

Nopco Agrimul 60 (Nopco Chemical Co.)- - - Kerosene and turpentine 

Nopco 1219-A (Nopco Chemical Co.)- - - - - Kerosene 

Nopco HBX-2 (Nopco Chemical Co.) ----- Kerosene 

Skil 181 -A (Gallowhur Chemical Corp.) - - - Kerosene 

Tenlo 400 (Griffin Chemical Co.)- ----- - Kerosene and turpentine 

Trex 45 (Griffin Chemical Co.)-------- Turpentine 

Trex 80 (Griffin Chemical Co.) Turpentine 



- 4 



The kerosene-type concentrates containing Emulsifier R, Tenlo 400, 
or Duponol G were stable in 1 -percent sodium chloride solution for a 
week. Many of the concentrates that did not meet these criteria may be 
suitable for other purposes, such as use in sprays. 

Commercial concentrates . --The amounts of bottom creaming in 
emulsions prepared from the three commercial concentrates after they 
had stood for 7 days are shown below. 



Diluent 



B 



Distilled water 




Trace 


1 mm. 


1 mm . 


Sodium chloride 




Broken 


Trace 


Broken 


Acetic acid 




Broken 


2 mm . 


2 mm. 


Ammonium hydrc 


xide 


2 mm 


1 mm. 


3 mm. 


Tap water 




1 mm. 


Trace 


3 mm . 



Emulsions A and C showed nearly complete top clearing and particles 
were discernible upon resuspension. 

It is apparent that concentrates A and C do not meet the criteria 
established. Except for extent of creaming, concentrate B does meet 
these criteria. 

This report does not constitute a condemnation of any of these prod- 
ucts. Two of them are being used extensively and successfully in Texas, 
although there have been reports (Radeleff and Bushland 1950) of cattle 
killed by dipping in vats in which such emulsions had deteriorated. 



Miscellaneous formulations. --Of 23 miscellaneous formulations 



tested, 19 were either recommended by emulsifier producers or supplied 
by them for evaluation; the remaining 4 were arbitrarily compounded in 
the laboratory. Formulations containing the following emulsifiers and 
solvents were found to be satisfactory. 



Emulsifier 






Solvent 


P 


erce 


nt 


Percent 


Emcol H-66 


35 




Deodorized kerosene 15 


Antarox A-200 


50 




None 


Antarox B-290 


50 




None 


Antarox B-201 


35 




Butyl Cellosolve 15 


Ahcowet RS 


50 




None 




60 




None 


Ahco RL-382 


16 




Kerosene 26 


G-89K. 1 (Atlas Powder Co.) 


50 




None 




45 




Kerosene 10 



All formulations except those containing Antarox A- 200 or Ahco 
RL-382 formed solubilized systems when diluted with water. The 
degree of transparency varied, but the most opaque materials showed 
no sign of creaming at the end of a week in the vials. Formulations 
containing Ahcowet RS and Ahco RL-382 broke in 1 -percent sodium 
chloride solution. 

Experiments in miniature vats . --The validity of this method for 
selecting formulations for further development has been supported by 
two experiments conducted in miniature (7 -gallon) concrete dipping vats. 
In the first experiment - ^ four formulations prepared in the laboratory and 
two commercial concentrates (A and C) were used. Under similar con- 
ditions of vat-charging methods, climate, contamination, and time, the 
laboratory-prepared formulations showed less deterioration than the 
commercial formulations. 

Two of the miscellaneous solubilizable concentrates were included 
in these tests. Although they showed no oil separation or gumminess, 
one of them developed a thick pellicle at its surface. The other concen- 
trate showed evidence of creaming, but upon agitation the cream was 
resolubilized. 

Conclusions 

These experiments indicate that certain combinations of emulsifier, 
solvent, and toxaphene produce emulsifiable concentrates that are more 
stable than some commercial formulations when diluted and held under 
laboratory conditions. It is to be emphasized that most of the results 
were obtained in laboratory glassware. The confirmatory tests with 
emulsions held in miniature vats do not represent actual field observa- 
tions. However, the formulations that performed better under those 
limited experimental conditions merit further testing in ranch vats. 

Literature Cited 

Radeleff, R. D. , and Bushland, R. C. 

1950. Acute toxicity of chlorinated insecticides applied to livestock. 
Jour. Econ. Ent. 43(3): 358-364. 



3/ Conducted by R. D. Radeleff (unpublished report) . 



UNIVERSITY OF FLORIDA 
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